You can go with the really short method:
The only problem with that method is that some web hosts have url access blocked in the file methods, for security reasons. You may be able to use this workaround method instead:
$str = file_get_contents($url);
You should now have the contents of the website in a string variable. Note that this doesn’t pull down the supporting files such as javascript or CSS. You will have to further parse the page and retrieve those seperately if you need the whole thing.